Hydraulic ram pump devices are known in the art. Such pump devices typically comprise a supply tube for receiving a liquid with a relatively low head, an accumulator connected to the supply tube via a one-way valve, an outlet tube from the accumulator for producing liquid with a relatively high head. An outlet valve, provided at an outlet of the supply tube, after the accumulator, outlet opens and shuts the outlet at the supply tube. Such hydraulic ram pumps have long been known in the art.
In such a Prior Art design, the outlet valve may be provided with a float, which is closed at a certain liquid flow, and opened again when the liquid flow has ceased. Such a pump operates well as long as the liquid fed, usually water, is free from impurities. Even small impurities may, however, disturb the operation of such an outlet valve, whereby the pump device of this type ceases to operate.
Thus there remains in the art a demand for hydraulic ram pump devices which are not disturbed by a reasonable amount of impurities in the actual liquid, and this have a reliable function and are simple in design and thus cheap in manufacture.